Embodiments of the invention relate to quantized congestion notification (QCN) for computing environments and, in particular, providing QCN for OpenFlow networks/Software Defined Networks (SDN).
QCN is an end-to-end congestion avoidance technique where the end-node/Reaction Point (RP) throttle the communication traffic flow based on Congestion Notification Messages (CNM) feedback from the Congestion Points (CP), such as edge bridge switches. With QCN, the congestion checks and CNM generation are performed in hardware. The CNMs are relayed to the RP indirectly through each CP. At the end-station or node, the RP implements queues in the network interface card (NIC)/converged network adapter (CNA) and react to CNMs messages to reduce or eliminate congestion and packet drop.